Herpes simplex virus type 1 (HSV-1) is a clinically relevant pathogen infecting 150 to 200 million Americans in which 20% will experience recurrent reactivation of latent virus. In the ophthalmic community, it is the leading cause of infectious corneal blindness in the industrialized world as a result of reactivation of latent virus. The prevalence and success of this virus is thought to reside in the immune evading mechanisms that have developed through co-evolution with the human host. Type I interferons (IFN) are a principal target of the virus countering resistance to the anti-viral effects of this cytokine. We have established pathways necessary for type I IFN-induced resistance to acute ocular HSV-1 and genital HSV-2 infection. We have also identified efficacious and non-efficacious type I IFN transgenes and have begun a discovery proteomics approach to identify proteins specifically modified by the efficacious type I IFN transgene. Preliminary data also suggest type I IFN and IFN-gamma (type II IFN) transgenes are able to partially or completely block HSV-1 reactivation in TG explant cultures. Based on our promising preliminary results and ongoing study, we propose to test the hypothesis that type I and type II IFNs block HSV-1 reactivation in vitro and in vivo through novel processes that may be independent of conventional IFN-inducible pathways including OAS and PKR. To test this hypothesis, we plan to: 1) characterize the predicted synergistic effect of type I and type II IFN in the prevention of HSV-1 reactivation in TG explant cultures, 2) characterize the effect of type I and type II IFN in hindering HSV-1 reactivation in vivo or in blocking the trafficking of virus placed into the sensory ganglion from reaching the cornea of naive mice, 3) characterize the tissue-specific nature of IFN- inducible, anti-viral pathways using transgenic mice expressing type I IFN in the central nervous system that have dysfunctional OAS or PKR pathways, and 4) using discovery and functional proteomics, identify and characterize unique proteins modified by efficacious type I IFN transgene treatment in trigeminal ganglia following in situ transfection. It is anticipated that in achieving this goal, significant insight will be accomplished in the identification of pathways involved in blocking HSV-1 reactivation and spread within the nervous system.